title: Effects of gasoline engine emissions on preexisting allergic airway responses in mice.
abstract: Gasoline-powered vehicle emissions contribute significantly to ambient air pollution. We hypothesized that exposure to gasoline engine emissions (GEE) may exacerbate preexisting allergic airway responses. Male BALB/c mice were sensitized by injection with ovalbumin (OVA) and then received a 10-min aerosolized OVA challenge. Parallel groups were sham-sensitized with saline. Mice were exposed 6 h/day to air (control, C) or GEE containing particulate matter (PM) at low (L), medium (M), or high (H) concentrations, or to the H level with PM removed by filtration (high-filtered, HF). Immediately after GEE exposure mice received another 10-min aerosol OVA challenge (pre-OVA protocol). In a second (post-OVA) protocol, mice were similarly sensitized but only challenged to OVA before air or GEE exposure. Measurements of airway hyperresponsiveness (AHR), bronchoalveolar lavage (BAL), and blood collection were performed approximately 24 h after the last exposure. In both protocols, M, H, and HF GEE exposure significantly decreased BAL neutrophils from nonsensitized mice but had no significant effect on BAL cells from OVA-sensitized mice. In the pre-OVA protocol, GEE exposure increased OVA-specific IgG(1) but had no effect on BAL interleukin (IL)-2, IL-4, IL-13, or interferon (IFN)-gamma in OVA-sensitized mice. Nonsensitized GEE-exposed mice had increased OVA-specific IgG(2a), IgE, and IL-2, but decreased total IgE. In the post-OVA protocol, GEE exposure reduced BAL IL-4, IL-5, and IFN-gamma in nonsensitized mice but had no effect on sensitized mice. These results suggest acute exposure to the gas-vapor phase of GEE suppressed inflammatory cells and cytokines from nonsensitized mice but did not substantially exacerbate allergic responses.
authors.affiliation: Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108, USA.
authors.forename: Kimberly C
authors.initials: KC
authors.lastname: Day
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Reed
authors.forename: Jacob D
authors.initials: JD
authors.lastname: McDonald
authors.forename: Steven K
authors.initials: SK
authors.lastname: Seilkop
authors.forename: Edward G
authors.initials: EG
authors.lastname: Barrett
mesh_terms: D000818:Animals; D005742:Gasoline / Q000633:toxicity*; D019570:Inhalation Exposure; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D052638:Particulate Matter / Q000008:administration & dosage / Q000633:toxicity; D012130:Respiratory Hypersensitivity / Q000139:chemically induced / Q000276:immunology* / Q000378:metabolism*; D001335:Vehicle Emissions
chemical_list: D005742:Gasoline; D052638:Particulate Matter; D001335:Vehicle Emissions; D010047:Ovalbumin